Toxic insects advertise their defended state to potential predators using warning displays. Frequently these displays use cues through more than one sensory modality, and combine color, smell and sound to produce a mu...Toxic insects advertise their defended state to potential predators using warning displays. Frequently these displays use cues through more than one sensory modality, and combine color, smell and sound to produce a multimodal warning display. Signalling through more than one sensory pathway may enhance the rate of avoidance learning, and the memorability of the learned avoidance. A common insect warning odor, pyrazine, has previously been shown to increase the rate of learned avoidance of unpalatable yellow prey by domestic chicks （GaUus gallus domesticus）, and the odor also improved memory of this learned avoidance. However, to date no research has examined this response to pyrazine odor using wild birds under natural conditions. This study used wild robins （Erithacus rubecula） to investigate whether wild birds avoided yellow baits that smelled of pyrazine more strongly than those presented with no odor. The results provide some evidence that pyrazine odor does increase the level of protection an aposematic insect gains from a wild avian predator, but that the effect of pyrazine on learned avoidance was much weaker than was found with domestic chicks .展开更多
Dear Editor,Over the past decades,cooperative control and distributed optimization have gained significant research attention due to their broad applications such as signal processing,robotics,and social networks[1],[...Dear Editor,Over the past decades,cooperative control and distributed optimization have gained significant research attention due to their broad applications such as signal processing,robotics,and social networks[1],[2].As a fundamental component of distributed control and optimization,the issue of average consensus has become a recurring topic of interest[3],[4].展开更多
Pierre Robin综合征(pierre robin syndrome, PRS)是一种相对罕见的疾病。喂养困难是患病婴幼儿最主要的功能障碍,若不及时识别和治疗,会使患儿营养的摄入与需求失衡,影响患儿生长发育,降低其免疫力。本文就PRS患儿喂养困难的界定、影...Pierre Robin综合征(pierre robin syndrome, PRS)是一种相对罕见的疾病。喂养困难是患病婴幼儿最主要的功能障碍,若不及时识别和治疗,会使患儿营养的摄入与需求失衡,影响患儿生长发育,降低其免疫力。本文就PRS患儿喂养困难的界定、影响因素、发生机制及各类管理策略进行综述,为进一步展开研究、改善PRS患儿喂养困难提供借鉴。展开更多
本文运用 Leggett-Williams 不动点定理讨论了具有平均曲率算子 Robin 边值问题三个正解的存在性, 其中, Z 表示整数集,[1, T ]Z := {1, 2, ..., T − 1, T}, T ≥ 2 是正整数,, s ∈ (−1, 1),非线性项 f : [1, T ]Z × [0, ∞) → [...本文运用 Leggett-Williams 不动点定理讨论了具有平均曲率算子 Robin 边值问题三个正解的存在性, 其中, Z 表示整数集,[1, T ]Z := {1, 2, ..., T − 1, T}, T ≥ 2 是正整数,, s ∈ (−1, 1),非线性项 f : [1, T ]Z × [0, ∞) → [0, ∞) 连续,∆ 是前项差分算子。展开更多
自20世纪20年代以来,"下颌短小后缩畸形、舌后垂和呼吸道阻塞"被确定为Pierre Robin序列征(Pierre Robin syndrome,PRS)。PRS可单独发生或合并其他综合征,如第一、二腮弓综合征及其他相关综合征。PRS可导致新生儿呼吸困难和...自20世纪20年代以来,"下颌短小后缩畸形、舌后垂和呼吸道阻塞"被确定为Pierre Robin序列征(Pierre Robin syndrome,PRS)。PRS可单独发生或合并其他综合征,如第一、二腮弓综合征及其他相关综合征。PRS可导致新生儿呼吸困难和进食困难,患有严重PRS的儿童可能在出生后不久死于呼吸道阻塞;胎儿期早期诊断可于分娩后得到及时治疗,因此PRS的早期诊断非常重要,可为PRS的早期诊断提供更客观的依据。本文主要介绍近年来影像学早期诊断和三维数字化技术在PRS诊断方面的研究进展。展开更多
A mimetic finite difference scheme for the transient heat equation under Robin’s conditions is presented. The scheme uses second order gradient and divergence mimetic operators, on a staggered grid, to approximate th...A mimetic finite difference scheme for the transient heat equation under Robin’s conditions is presented. The scheme uses second order gradient and divergence mimetic operators, on a staggered grid, to approximate the space derivatives. The temporal derivative is replaced by a first order backward difference approximation to obtain an implicit formulation. The resulting scheme contains nonstandard finite difference stencils. An original convergence analysis by the matrix’s method shows that the proposed scheme is unconditionally stable. A comparative study against standard finite difference schemes, based on central difference or first order one side approximations, reveals the advantages of our scheme without being its implementation more expensive or difficult to achieve.展开更多
Within some 40 hours,Elon Musk’s high-calibre whirlwind trip to Beijing and Shanghai from 30 May to 1 June saw him meeting with high-ranking Chinese officials,in addition to visiting his electric car company Tesla’s...Within some 40 hours,Elon Musk’s high-calibre whirlwind trip to Beijing and Shanghai from 30 May to 1 June saw him meeting with high-ranking Chinese officials,in addition to visiting his electric car company Tesla’s Gigafactory.He also had in-person discussion with Robin Zeng,the founder of electric vehicle(EV)battery maker Contemporary Amperex Technology Co.Ltd.As Tesla is expanding in the Chinese market and beyond,so too are its Chinese counterparts,leading to China’s rise to become the world’s largest auto exporter.展开更多
文摘Toxic insects advertise their defended state to potential predators using warning displays. Frequently these displays use cues through more than one sensory modality, and combine color, smell and sound to produce a multimodal warning display. Signalling through more than one sensory pathway may enhance the rate of avoidance learning, and the memorability of the learned avoidance. A common insect warning odor, pyrazine, has previously been shown to increase the rate of learned avoidance of unpalatable yellow prey by domestic chicks （GaUus gallus domesticus）, and the odor also improved memory of this learned avoidance. However, to date no research has examined this response to pyrazine odor using wild birds under natural conditions. This study used wild robins （Erithacus rubecula） to investigate whether wild birds avoided yellow baits that smelled of pyrazine more strongly than those presented with no odor. The results provide some evidence that pyrazine odor does increase the level of protection an aposematic insect gains from a wild avian predator, but that the effect of pyrazine on learned avoidance was much weaker than was found with domestic chicks .
基金supported in part by the National Natural Science Foundation of China(62173087)the Fundamental Research Funds for the Central Universitiesthe Alexander von Humboldt Foundation of Germany。
文摘Dear Editor,Over the past decades,cooperative control and distributed optimization have gained significant research attention due to their broad applications such as signal processing,robotics,and social networks[1],[2].As a fundamental component of distributed control and optimization,the issue of average consensus has become a recurring topic of interest[3],[4].
文摘Pierre Robin综合征(pierre robin syndrome, PRS)是一种相对罕见的疾病。喂养困难是患病婴幼儿最主要的功能障碍,若不及时识别和治疗,会使患儿营养的摄入与需求失衡,影响患儿生长发育,降低其免疫力。本文就PRS患儿喂养困难的界定、影响因素、发生机制及各类管理策略进行综述,为进一步展开研究、改善PRS患儿喂养困难提供借鉴。
文摘本文运用 Leggett-Williams 不动点定理讨论了具有平均曲率算子 Robin 边值问题三个正解的存在性, 其中, Z 表示整数集,[1, T ]Z := {1, 2, ..., T − 1, T}, T ≥ 2 是正整数,, s ∈ (−1, 1),非线性项 f : [1, T ]Z × [0, ∞) → [0, ∞) 连续,∆ 是前项差分算子。
文摘自20世纪20年代以来,"下颌短小后缩畸形、舌后垂和呼吸道阻塞"被确定为Pierre Robin序列征(Pierre Robin syndrome,PRS)。PRS可单独发生或合并其他综合征,如第一、二腮弓综合征及其他相关综合征。PRS可导致新生儿呼吸困难和进食困难,患有严重PRS的儿童可能在出生后不久死于呼吸道阻塞;胎儿期早期诊断可于分娩后得到及时治疗,因此PRS的早期诊断非常重要,可为PRS的早期诊断提供更客观的依据。本文主要介绍近年来影像学早期诊断和三维数字化技术在PRS诊断方面的研究进展。
文摘A mimetic finite difference scheme for the transient heat equation under Robin’s conditions is presented. The scheme uses second order gradient and divergence mimetic operators, on a staggered grid, to approximate the space derivatives. The temporal derivative is replaced by a first order backward difference approximation to obtain an implicit formulation. The resulting scheme contains nonstandard finite difference stencils. An original convergence analysis by the matrix’s method shows that the proposed scheme is unconditionally stable. A comparative study against standard finite difference schemes, based on central difference or first order one side approximations, reveals the advantages of our scheme without being its implementation more expensive or difficult to achieve.
文摘Within some 40 hours,Elon Musk’s high-calibre whirlwind trip to Beijing and Shanghai from 30 May to 1 June saw him meeting with high-ranking Chinese officials,in addition to visiting his electric car company Tesla’s Gigafactory.He also had in-person discussion with Robin Zeng,the founder of electric vehicle(EV)battery maker Contemporary Amperex Technology Co.Ltd.As Tesla is expanding in the Chinese market and beyond,so too are its Chinese counterparts,leading to China’s rise to become the world’s largest auto exporter.
